from django.shortcuts import render, redirect
from .models import Topic, Entry
from .forms import TopicForm, EntryForm


def index(request):
    """学习笔记的主页"""
    return render(request, "learning_logs/index.html")


def topics(request):
    """显示所有的主题"""
    topics = Topic.objects.order_by("date_added")
    context = {"topics": topics}
    return render(request, "learning_logs/topics.html", context)


def topic(request, topic_id):
    """显示单个主题的及其所有的条目"""
    topic = Topic.objects.get(id=topic_id)
    entries = topic.entry_set.order_by("-date_added")
    context = {"topic": topic, "entries": entries}
    return render(request, "learning_logs/topic.html", context)


def new_topic(request):
    """添加新主题"""
    if request.method != "POST":
        # 未提交数据：创建一个新表单
        form = TopicForm()
    else:
        # POST提交的数据，对数据进行处理
        form = TopicForm(data=request.POST)
        if form.is_valid():
            form.save()
            return redirect("learning_logs:topics")

    # 显示空表单或指出表单数据无效
    context = {"form": form}
    return render(request, "learning_logs/new_topic.html", context)


def new_entry(request, topic_id):
    """在特定主题中添加新条目"""
    topic = Topic.objects.get(id=topic_id)

    if request.method != "POST":
        # 未提交数据，创建一个空表单
        form = EntryForm()
    else:
        # POST提交的数据，对数据进行处理
        form = EntryForm(data=request.POST)
        if form.is_valid():
            new_entry = form.save(commit=False)
            new_entry.topic = topic
            new_entry.save()
            return redirect("learning_logs:topic", topic_id=topic_id)

    # 显示空表单或指出表单无效
    context = {"topic": topic, "form": form}
    return render(request, "learning_logs/new_entry.html", context)


def edit_entry(request, entry_id):
    """编辑既有的条目"""
    entry = Entry.objects.get(id=entry_id)
    topic = entry.topic

    if request.method != "POST":
        # 初次请求：使用当前的条目填充表单
        form = EntryForm(instance=entry)
    else:
        # POST提交的数据：对数据进行处理
        form = EntryForm(instance=entry, data=request.POST)
        if form.is_valid():
            form.save()
            return redirect("learning_logs:topic", topic_id=topic.id)

    context = {"entry": entry, "topic": topic, "form": form}
    return render(request, "learning_logs/edit_entry.html", context)
